Natural Cycles, a contraception app, has been banned from advertising itself as "highly effective" on Facebook adverts.

The UK's Advertising Standards Authority warned Natural Cycles "not to exaggerate" its effectiveness. When used perfectly the app claims to be 99 per cent effective, but this is more like 93 per cent if used under normal circumstances.

Claims the app was "highly accurate" and "provided a clinically tested alternative to other birth control methods" were found to be misleading, causing the advert to be banned from Facebook.

Many women are choosing to stop using hormone based methods and instead opt for more natural forms of contraception as a result, such as Natural Cycles. It monitors the user's temperature to track fertility, because your temperature rises when you ovulate, meaning they can say when it's okay to safely have sex during your cycle.

The ASA found there to be too big a variation between the typical use of the app and the perfect scenario. The figures used in the advert were based on perfect use which is hard to achieve for the average user, and so the app can no longer be described as "highly effective".

The service costs £39.99 upfront with the thermometer included or if you don't fancy shelling out 40 quid you can have a free trial month and then pay £5.99 per month.

Susanna, an Edinburgh uni student who was using the app until February this year said: "I think it's good it's banned, a lot of young people use social media and I think there’s a filter over social media where people forget it’s real. I felt mislead.

"I think people need to be made aware of the risks, and it’s hard to do that properly when you’re advertising over social media."

Natural Cycles have said: "We are committed to being open and transparent in our communications to ensure our message is clear and provides women with the information they need to determine if Natural Cycles is right for them. As part of these efforts, every advertisement undergoes a strict approval process.

"Natural Cycles has been independently evaluated and cleared by regulators in Europe and the US based on clinical evidence demonstrating its effectiveness as a method of contraception."